Application of modified export coefficient model to estimate nitrogen and phosphorus pollutants from agricultural non-point source

There is a great uncertainty in generation and formation of non-point source (NPS) pollutants, which leads to difficulties in the investigation of monitoring and control. However, accurate calculation of these pollutant loads is closely correlated to control NPS pollutants in agriculture. In addition, the relationships between pollutant load and human activity and physiographic factor remain elusive. In this study, a modified model with the whole process of agricultural NPS pollutant migration was established by introducing factors including rainfall driving, terrain impact, runoff index, leaching index and landscape intercept index for the load calculation. Partial least squares path modeling was applied to explore the interactions between these factors. The simulation results indicated that the average total nitrogen (TN) load intensity was 0.57 t km-2 and the average total phosphorus (TP) load intensity was 0.01 t km-2 in Chengdu Plain. The critical effects identified in this study could provide useful guidance to NPS pollution control. These findings further our understanding of the NPS pollution control in agriculture and the formulation of sustainable preventive measures.

Automated summary

There is a great uncertainty in the generation and formation of non-point source pollutants in agriculture, making it difficult to investigate and control these pollutants. This study established a modified model to calculate the pollutant loads, considering factors such as rainfall, terrain, runoff, leaching, and landscape intercept. The findings provide useful guidance for controlling non-point source pollution and advancing sustainable preventive measures in agriculture.